1. Field of the Invention
The present invention relates to a cBN (cubic boron nitride) semiconductor device. More particularly, it relates to a technique of forming an ohmic electrode on a cBN semiconductor device of an n-type, a p-type or a pn junction type. The cBN semiconductor device is used as a solid electronic element, an optoelectronic element for rectifiers, transistors, light emitting diodes and so on and integrated elements thereof.
2. Discussion of Background
cBN is a semiconductor material having an indirect gap which is considered to be about 6.3 eV, and it is possible to form a pn junction, whereby the device can be used as a rectifier element or a light emitting diode. However, there has not been exemplified that an electrode attached to a cBN crystal of a p-type or an n-type shows an ohmic property. Nevertheless, a silver paste has been used for the cBN as an electrode in spite of its non-ohmic characteristic. Although there is a report wherein Ti is used for an electrode, it has not been shown that a Ti electrode has ohmic characteristic.